﻿#include "my_stdio.h"
#include <string.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
mFILE* mfopen(const char* filename, const char* mode)
{
	int fd = -1;
	if (strcmp(mode, "r") == 0)
	{
		fd = open(filename, O_RDONLY);
	}
	else if (strcmp(mode, "w") == 0)
	{
		fd = open(filename, O_CREAT | O_WRONLY | O_TRUNC, 0666);
	}
	else if (strcmp(mode, "a") == 0)
	{
		fd = open(filename, O_CREAT | O_WRONLY | O_APPEND, 0666);
	}
	if (fd < 0) return NULL;
	mFILE* mf = (mFILE*)malloc(sizeof(mFILE));
	if (!mf)
	{
		close(fd);
		return NULL;
	}
	mf->fileno = fd;
	mf->flag = FLUSH_LINE;
	mf->size = 0;
	mf->cap = SIZE;
	return mf;
}
void mfflush(mFILE* stream)
{
	if (stream->size > 0)
	{
		// 写到内核⽂件的⽂件缓冲区中!
		write(stream->fileno, stream->outbuffer, stream->size);
		// 刷新到外设
		fsync(stream->fileno);
		stream->size = 0;
	}
}
int mfwrite(const void* ptr, int num, mFILE* stream)
{
	// 1. 拷⻉
	memcpy(stream->outbuffer + stream->size, ptr, num);
	stream->size += num;
	// 2. 检测是否要刷新
	if (stream->flag == FLUSH_LINE && stream->size > 0 && stream->outbuffer[stream->size - 1] == '\n')
	{
		mfflush(stream);
	}
	return num;
}
void mfclose(mFILE* stream)
{
	if (stream->size > 0)
	{
		mfflush(stream);
	}
	close(stream->fileno);
}